This one's going to be short and sweet…
Making good on their promise to release by the end of June, Microsoft announced today that Service Pack 1 for SharePoint 2010 is now available for download. You'll find an important note, along with the order in which the service packs should be installed, FAQs, and additional resources in the announcement post on the Microsoft SharePoint Team Blog.
Needless to say, you'll want to read the installation instructions posted on the SharePoint Team Blog first, but here is the download page for the SharePoint Server 2010 and Office Server 2010 SP1 packages themselves, and it's also worth noting that that there is also a separate download page dedicated to the Office 2010 SP1 packages.
Merry Service Pack 1 day, everybody!